Chitosan flocculation associated with biofilms of C. saccharolyticus and C. owensensis enhances biomass retention in a CSTR

Vongkampang, Thitiwut; Rao, Nikhil Seshagiri; Grey, Carl; Niel, Ed W. J. van

doi:10.1016/j.ijhydene.2021.03.230

Cited by 4 publications

(5 citation statements)

References 39 publications

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“…(28) Chitosan has the potential to be used in an immobilization technique for retaining biomass of Caldicellulosiruptor species at a lower concentration of 1 mg L. This property was associated with natural biofilm produced by C. owensensis in the chemostat at higher maximum dilution rate (D). (29) Unlike the present research, 200 μL of 0.1% crystal violet is added to each well and the microtiter plates are incubated at room temperature for 20 min. The biofilm layer is then dissolved by adding 150 μl of 33% acetic acid to each well.…”

Section: Discussionmentioning

confidence: 99%

Influence of interspecies interactions on biomass and extracellular polymeric substances of bacterial biofilms

Alava

Maddela

2023

Univ Med

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BackgroundStudies with emphasis on pure and mixed-species biofilms are of significant importance in understanding biofilm formation mechanisms during microbial infections. This research aims to evaluate pure- and dual-species biofilms of Escherichia coli (code A), Staphylococcus aureus (code B), Klebsiella pneumoniae (code C) and Pseudomonas aeruginosa (code D) pathogenic bacterial species and their production of biofilm exopolysaccharides at laboratory scale. MethodsBiofilm biomass (A595) of pure- and dual-species cultures was determined by means of a microtiter plate assay in triplicate using a microplate photometer (Fisher Scientific, type-357). Extracellular polymeric substances (EPS) and soluble microbial products (SMP) were extracted from the biofilm cells (pure- and dual-species cultures) using the alkaline-heat extraction method. Dry weights (g/L) of EPS and SMP were determined by drying the samples at 105 °C for 8 hours. ResultsKlebsiella pneumoniae biofilm biomass accounted for a 28-72% greater biofilm biomass than the other bacteria. Experimental values of dual-species biofilm biomasses were in the range of 6% to 30% over theoretical values. The experimental value of one dual-species (bacteria B + D) biofilm biomass was 30% higher than its expected value. Decrease or increase in the dual-species biofilm biomass of either bacteria A+C or bacteria B+C combinations was totally dependent on the cell density of bacteria C. Conclusions Biofilm biomass of pure-species cultures was totally species-dependent, and the biofilm biomass of four species was in the following order: bacteria C > D > A > B. Relation between biofilm biomasses and SMP or EPS was inconsistent.

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Section: Discussionmentioning

confidence: 99%

Influence of interspecies interactions on biomass and extracellular polymeric substances of bacterial biofilms

Alava

Maddela

2023

Univ Med

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“…The high rate of H 2 production was associated with the acetate formation as the main metabolic by-product [10,32]. However, the formation of some reduced products, such as lactate drains electrons from H 2 production [32,33].…”

Section: Effect Of Initial Substrate Concentrationmentioning

confidence: 99%

“…The early washout of T. maritima cells that was observed at a D of0.45 h -1 could be explained by the shift of the metabolism of T. maritima to lactate formation (21 mmol/L). In fact, lactate pathway is considered less energetically than acetate pathway as it yields to only 2 moles of ATP, resulting in lower values of µ max and cell yields [33].…”

Section: Effect Of the Applied Dilution Ratementioning

confidence: 99%

Improvement of Biohydrogen Production from Date Wastes by Thermotoga maritima Using a Continuous Anaerobic Membrane Bioreactor

Saidi

Hamdi

Bouallagui

2022

Waste Biomass Valor

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Hydrogen (H 2 ) is a promising energy carrier owing to its environmentally friendly properties and high energy content. The aim of this work is to achieve a continuous H 2 production from a simpli ed culture medium composed of date wastes (DW) and natural seawater using the marine bacterium, Thermotoga maritima . Increasing the dilution rate ( D ) from 0.02 to 0.25 h -1 in the continuous stirred tank reactor (CSTR) improved the volumetric H 2 production rate ( Q H2 ) from 2 to 17 mmol/L.h. At a D above 0.25 h -1 , a washout of the bacterium cells was observed, resulting in a signi cant decrease of biomass concentration (BC) and then the drop in Q H2 . The production of H 2 was improved by using a membrane bioreactor (MBR) due to the cell retention in the reactor. At a high D of 0.6 h -1 , the maximum Q H2 was increased from 0.6 to 61.75 mmol/L.h, which is higher than those previously reported on continuous H 2 production from different substrates. Moreover, increasing the hexose concentration in the date juice (DJ) from 30 to 60 mmol/L further enhanced the H 2 production. It allowed a Q H2 . of 70.2 mmol/L.h which is interesting for a large scale production of H 2 from date wastes. Statement Of NoveltyBiological valorization of date wastes is a challenge due to their high biodegradable organic matter and sugar contents. The present study investigates for the rst time the continuous production of H 2 by the halophilic bacterium T. maritima from a simpli ed culture medium composed of date wastes and seawater in a CSTR and an MBR processes. Our previous works (Saidi et al., 2017) showed that using seawater is an alternative solution for scaling-up the batch fermentation process. In this work, results showed that H 2 production has increased signi cantly in the MBR due to the retention of biomass, yielding a maximum Q H2 of 70.2 mmol/L.h at a high D of 0.6 h -1 . Therefore, using seawater medium with membrane bioreactor can provide a better solution for date wastes management, e cient renewable energy production and minimization of freshwater consumption.

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“…In general, this biopolymer is obtained by partial de-acetylation of chitin [ 24 ], resulting in a random distribution of the two monomers. Although chitosan has an antimicrobial property, a previous study established safe conditions for Caldicellulosiruptor species to enable chitosan to be used for cell immobilization [ 25 ]. However, immobilization with chitosan did not achieve the desired volumetric hydrogen productivity (Q H2 ).…”

Section: Introductionmentioning

confidence: 99%

“…However, immobilization with chitosan did not achieve the desired volumetric hydrogen productivity (Q H2 ). Nevertheless, a combination of chitosan with acrylic fibres as carriers led to stable biofilms, thereby improving Q H2 [ 25 ]. Acrylic fibres are linear polymer synthesized from polyacrylonitrile (PAN) (C 3 H 3 N) n [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Immobilization techniques improve volumetric hydrogen productivity of Caldicellulosiruptor species in a modified continuous stirred tank reactor

Vongkampang

Sreenivas

Grey

et al. 2023

Biotechnol Biofuels

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Background Co-cultures and cell immobilization have been used for retaining biomass in a bioreactor, with the aim to improve the volumetric hydrogen productivity (QH2). Caldicellulosiruptor kronotskyensis is a strong cellulolytic species that possesses tāpirin proteins for attaching on lignocellulosic materials. C. owensensis has its reputation as a biofilm former. It was investigated whether continuous co-cultures of these two species with different types of carriers can improve the QH2. Results QH2 up to 30 ± 0.2 mmol L−1 h−1 was obtained during pure culture of C. kronotskyensis with combined acrylic fibres and chitosan. In addition, the yield of hydrogen was 2.95 ± 0.1 mol H2 mol−1 sugars at a dilution rate (D) of 0.3 h−1. However, the second-best QH2 26.4 ± 1.9 mmol L−1 h−1 and 25.4 ± 0.6 mmol L−1 h−1 were obtained with a co-culture of C. kronotskyensis and C. owensensis with acrylic fibres only and a pure culture of C. kronotskyensis with acrylic fibres, respectively. Interestingly, the population dynamics revealed that C. kronotskyensis was the dominant species in the biofilm fraction, whereas C. owensensis was the dominant species in the planktonic phase. The highest amount of c-di-GMP (260 ± 27.3 µM at a D of 0.2 h−1) were found with the co-culture of C. kronotskyensis and C. owensensis without a carrier. This could be due to Caldicellulosiruptor producing c-di-GMP as a second messenger for regulation of the biofilms under the high dilution rate (D) to prevent washout. Conclusions The cell immobilization strategy using a combination of carriers exhibited a promising approach to enhance the QH2. The QH2 obtained during the continuous culture of C. kronotskyensis with combined acrylic fibres and chitosan gave the highest QH2 among the pure culture and mixed cultures of Caldicellulosiruptor in the current study. Moreover, it was the highest QH2 among all cultures of Caldicellulosiruptor species studied so far.

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Chitosan flocculation associated with biofilms of C. saccharolyticus and C. owensensis enhances biomass retention in a CSTR

Cited by 4 publications

References 39 publications

Influence of interspecies interactions on biomass and extracellular polymeric substances of bacterial biofilms

Influence of interspecies interactions on biomass and extracellular polymeric substances of bacterial biofilms

Improvement of Biohydrogen Production from Date Wastes by Thermotoga maritima Using a Continuous Anaerobic Membrane Bioreactor

Immobilization techniques improve volumetric hydrogen productivity of Caldicellulosiruptor species in a modified continuous stirred tank reactor

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